Thermal Conductivity of Molten Salt by MD Simulation. Optimization of Calculation Conditions

抄録

We have investigated the calculation conditions necessary for precise and efficient evaluation of the thermal conductivity of a molten salt based upon the equilibrium Green-Kubo formula by molecular dynamics simulation. The suitable parameters are also presented for the Ewald sums in the calculations of the interionic force and the energy current. The statistical error was estimated at ±10% under the calculation conditions. The dependence of the calculated results was examined on various calculation conditions. The number of time steps of at least 50000, which corresponds to 200 ps, was required in order to obtain a fully converged value of the time integral of the correlation functions. No significant dependence was found on the number of particles used in the simulated system compared with the statistical error. The dependence on the time step, the interval between time origins when the correlation functions were sampled, and the upper integral limit for the correlation functions was negligible compared with the statistical error. The addition of a small velocity vector to the ions, however, significantly influenced the calculated value of the thermal conductivity.